From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Hui Peng Date: Mon, 2 Jan 2023 22:05:45 +0000 Subject: [PATCH] Fix an OOB access bug in A2DP_BuildMediaPayloadHeaderSbc In A2DP_BuildCodecHeaderSbc when p_buf->offset is 0, the `-=` operation on it may result in integer underflow and OOB write with the computed pointer passed to A2DP_BuildMediaPayloadHeaderSbc. This is a backport of I45320085b1e458d3b0e0d86162a35aaaae7b34cb Test: atest net_test_stack_a2dp_codecs_native Ignore-AOSP-First: security Tag:#security Bug: 186803518 Change-Id: I4ff1a1de71884b8de23008b2569fdea3650e85ec (cherry picked from commit a710300216be4a86373a65c6a685aeef8509cfa7) Merged-In: I4ff1a1de71884b8de23008b2569fdea3650e85ec --- stack/a2dp/a2dp_sbc.cc | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/stack/a2dp/a2dp_sbc.cc b/stack/a2dp/a2dp_sbc.cc index 54c3d1a26..f42939d54 100644 --- a/stack/a2dp/a2dp_sbc.cc +++ b/stack/a2dp/a2dp_sbc.cc @@ -859,6 +859,11 @@ bool A2DP_BuildCodecHeaderSbc(UNUSED_ATTR const uint8_t* p_codec_info, BT_HDR* p_buf, uint16_t frames_per_packet) { uint8_t* p; + // there is a timestamp right following p_buf + if (p_buf->offset < 4 + A2DP_SBC_MPL_HDR_LEN) { + return false; + } + p_buf->offset -= A2DP_SBC_MPL_HDR_LEN; p = (uint8_t*)(p_buf + 1) + p_buf->offset; p_buf->len += A2DP_SBC_MPL_HDR_LEN;